With the development of science and technology, the operation interfaces of various electronic products have gradually become humanized in recent years. For example, through a touch panel, the user can directly operate on the screen with a finger or a stylus to input information/words/patterns, thus eliminating the trouble of using an input device such as a keyboard or a key. In fact, the touch screen is usually composed of a sensing panel and a display disposed behind the sensing panel. An electronic device judges the intention of the user's touch on the sensing panel according to the position of the touch on the sensing panel and the screen presented by the display at that time, and executes a corresponding operation result.
In the related art, a technical solution in which an active stylus is used to perform touch operation has been developed. An active stylus can generate a transmission signal to a touch screen, and an electronic device having a touch screen performs signal processing (such as a mixing operation) on the transmission signal after the transmission signal is received so as to determine the position where the touch occurs. In the related art, since the electronic device and the active stylus are independent devices respectively, the capacitive sensing circuit in the touch screen doesn't have the information about the phase of the transmission signal, causing the mixing module in the capacitive sensing circuit to start the mixing operation blindly at an inappropriate time and causing the output signal of the mixing module to exceed a dynamic range of its internal output circuit, thereby resulting in distortion of the output signal.
Therefore, there is a need for improvement in the related art.